Katie Carr, doctor (and self-declared 'good person'), has just had an affair. It's really not her fault - she is, after all, married to David: angry, cynical, negative (though undeniably funny) and a real pain to live with. But then David meets DJ GoodNews, astonishingly effective faith healer and do-gooder of the unbearably smug kind. And now David is good. Too good, actually - 'a liberal's worst nightmare', he starts to put theory into practice, giving away their kids toys, reaching out to the hopeless and homeless in a very personal and, for Katie, disturbing way. It seems to her that if charity begins at home, it may be time to move.